Apparatus for curing asbestoscement pipes



sept. 14, 1943. 1 A CANN APPARATUS FOR CURING ASBESTOSgCEMENT PIPE FiledMay 23, 1941 4 Sheets-Sheet l Fig. 1.

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sept. 14, 1943. ,1 A, CANN. y 2,329,184

APPARATUS PoR CURING AsBEsTos-CEMENT PIPE -Filed May 23, 1'941 4sheets-sheet `s Sept. 14, 1943. J. A. CANN 2,329,184

APPARATUSv FOR CURlNGr` ASBESTOS-CEMENT PIPE Filed May 23, 1941 4Sheets-Sheet 4 ArroP/vf/ Patented Sept. 14, v1943 NITED STATESvAPPARATUS FonfcuanvG/s'ss'roscErmNr rirEs John Arthur Cann, Biekley,England, assgnor to Turner & Newall Limited, Spotland, Rochdale,England, a. British company Y Application May 23, 19

41, Serial No. 394,909

In Great Britain May 27, 1940 7 Claims.

This invention relates to the production of pipes from asbestos-cementor like material, that is to say, brous material and a binding agentthat sets rigid from a plastic state. These pipes are commonly formed onmandrels, and at present 5 it is the usual practice to loosen-the pipeson the mandrels by a process known as calendering while theasbestos-cement is still moist, transfer the moist pipes to split woodenmandrels, and allow them to set and d ry on these wooden mandrels. 10There is a risk of the pipes becoming slightly warped during thissetting and drying. Moreover, it is necessary to maintain two sets ofmandrels in use, and of course the transfer from the one mandrel totheother is an undesirable oper- 15 ation, although it is necessary underthe present practice as the pipes take a long time to set.

Another object is to provide an apparatus in which the pipes may be setwhile still on the mandrels on which they were made. 20

A further object of my invention is to provide means for setting thepipes quickly at substantially atmospheric pressure'.-

Yet another object of my invention is to provide means for handlingthe'pipes before and vdur- 25 ing the setting without damaging them.

In proceeding in accordance with my invention, the coatings are loosenedon the mandrels and then, while stillen-the mandrels on which they wereformed, are placed at substantially vifilriios-0 pheric pressure in hothumid ai'r. :The/setting is accelerated by the heat, andwle the pipeshave set they are removed from the mandrels. It is necessary that theair should be humid, because, if it is not, water required forcompletely setting '35 the cement or other binder will be extracted fromthe pipes by the atmosphere, and the pipes will be weakened.The-temperature of the atmosphere should not exceed 150 F., since abvethis temperature the asbestos-cement tends to s well. On 4.0 the otherhand, if the temperature is ,low the setting time is prolonged. It 4ispreferred to maintain the temperature at or'above 125'?v F., as'by thismeans setting takes place in under an hour'. The mandrels mayadvantageously be slowly rotated while they are in a hot humid atmosfphere, as then any riskof the pipes sticking to the mandrels iseliminated.

In order to carry out the process of the inven- 50 tion, I have deviseda novel form of apparatus Y comprising a -chamber containing a runway ortrack along which Vthe mandrels roll in passing through the chamber,means for engaging the mandrels and causing' them to roll along the run-55 way or track, and means for maintaining humid*A the atmosphere in thechamber.

My invention will best be understood from the following description ofthe preferred embodiments of it, taken in conjunction with the annexeddrawings, in which- Figure 1 is an elevation of one treating chamberwith the side wall removed to show the internal parts;

Figure 2 is a section on the line II-II in Figure 1;

Figure 3 is an elevation, similar t6 Figure 1, of another chamber;

Figure 3a is an elevation of the right-hand end of the chamberillustrated in Figure 3; and

Figure 4 shows part of this secondY chamber to a larger scale. y

Referring first to Figures 1 and 2; the chamber is a rectangularstructure I which is wholly closed except for an opening at each end.Each opening is closed by a hinged door ily having balance.

weights 4 fixed to arms which lie outside thev commodate these tracks,YVCoatedrmandrels .2,

with their coatings'previously loosened by calenfdering, roll down therunway, the uncoated ends of the mandrels running on the tracks 6. Thetracks each have upstanding outer flanges I which act as guides vfor themandrels. When a mandrel arrives at a door 3- it hits the buiier 5 andopens thedoor, so that it passes through automatically, the door closingbehind it.

Inside the chamberthe mandrels are engaged by two rubber belts 8 whichpass around rollers. Each belt is engaged by two end rollers, one-ofwhich, 9, is fixed to a shaft I0 driven through v a chain wheel II, andthe other of which,V I2, 'is

fixed to a shaft I3. Each belt is also engaged by intermediate rollersI4 carried by. shafts I5. All theseirollers serve to pressthelower runsof 4I5- the belts downwards into contact with the uncoated ends of themandrels, so that the mandrels are caused to roll slowlythrough thechambeialong the runway. l

Asbestos-cement pipes naturally vary in diameter, some being made onmandrels only 4 inches in` diameter vand others made on mandrels thatmay be as large as 18 inches in diameter. In order to allow mandrels 0Ldierent sizes to be itreated, the end rollers I2 and intermediaterollers Il are made adjustable in position. Figure the end openings, thedoors being shaped tp/acy/f" 1 shows in full lines their position andthose of the belts for treating small mandrels, and in dotted lines thepositions for treating large mandrels. making the shafts I3 and I5slidable in guides I6 in the side walls of the chamber.

The atmosphere in the chamber is maintained hot, e. g. at 125'F., andhumid by means of a water bath 22 containing steam coils II. Thus thecoatings that form the pipes are set as the mandrels pass through thechamber.

In the chamber shown in Figures 3 and 4, `the rubber belts are replacedby chain conveyors 23 having projecting arms I8 which carry rollers I9.Asv each mandrel arrives it is engaged by a. pair of arms I8, as shownin Figure 4, and thus caused to travel through the chamber. The endchain wheels over which the conveyors pass are made adjustablevertically by being mounted in guides 2|, so as to accommodate mandrelsof different sizes. As an example, there may be ve inches betweensuccessive arms and then the rollers will engage a 4" diameter mandrelas shown in full lines in Figure 4 and an 1,8" diameter mandrel as shownin dotted lines in the same ligure. In the latter case the frictionalengagement of the rollers I9 with the top of the mandrelis enough tocause the mandrel to roll along the runway.

In either of the chambers illustrated, the escape of humid air when ,thedoors are opened may be reduced, if necessary, by the provision oftrapchambers, each with two doors, at each end.

Iclaim:

1. In an apparatus for use in treating asbestos-cement or like pipes inthe form of coatings on mandrels, in combination, a chamber, means insaid chamber forming a track along which mandrels` can roll, conveyormeans arranged to engage mandrels and cause them to roll along saidtrack means in said chamber, and means for maintaining humid /theatmosphere in the chamber. Y

2. In an apparatus for use in treating asbestos-cement or like pipes inthe form of coatings The necessary adjustment is efiected bytos-cementor like pipes in the form of coatings on mandrels, in combination, achamber, means in said chamber forming a track along which mandrels canroll, conveyor means in said chamber for moving mandrels on'said trackmeans, a plurality of projecting arms carried by said conveyor means andspaced to engage the ends of mandrels, mandrel-engaging rollers carriedby said arms, and means for driving said conveyor means, whereby tocause mandrels to roll along said track means.

4. In an4 apparatus for use in treating asbestos-cement or like pipes inthe form of coatings on mandrels, in combination, a chamber, means insaid chamber forming a track along which mandrels can roll, conveyormeans arranged to engage mandrels and cause them to roll along saidtrack means in said chamber, and means for adjusting the position ofsaid conveyor means relatively to said track means, whereby toaccommodate mandrels of dilerent sizes.

5. In an apparatus for use in treating asbestos-cement or like pipes inthe form of coatings on mandrels, in combination, a chamber, means insaid chamber forming a track along which mandrels can roll, conveyormeans arranged to engage mandrels and cause them to roll along saidtrack means in said chamber, a waterbath in said chamber, and means forheating said water bath to maintain a hot humid atmosphere in saidchamber.

6. In an apparatus for use in treating asbestos-cement or like pipes inthe form of coatings on mandrels, in combination, a chamber formed withan opening at each end for the entry and discharge respectively ofmandrels, means for closing each of said openings against the escape ofthe atmosphere within said chamber, means in said chamber in alignmentwith said openings and forming a track along which mandrels can roll,conveyor means arranged to engage mandrels and cause them to roll alongsaid track means in said chamber, and means for maintaining humid theatmosphere in the chamber.

7. In an apparatus for use in treating asbestos-cement or like pipes inthe `form of coatings on mandrels, in combination, a chamber, a pair ofspaced tracks in said chamber providing a runway along which theuncoated ends of-mandrels can roll, and an endless conveyor associatedwith each track and arranged to engage the mandrels and cause them toroll along said runway through said chamber.

JOHN ARTHUR CANN.

